Abstract
Program slicing is a well known family of techniques used to identify code fragments which depend on or are depended upon specific program entities. They are particularly useful in the areas of reverse engineering, program understanding, testing and software maintenance. Most slicing methods, usually oriented towards the imperative or object paradigms, are based on some sort of graph structure representing program dependencies. Slicing techniques amount, therefore, to ( sophisticated) graph transversal algorithms. This paper proposes a completely different approach to the slicing problem for functional programs. Instead of extracting program information to build an underlying dependencies' structure, we resort to standard program calculation strategies, based on the so-called Bird-Meertens formalism. The slicing criterion is specified either as a projection or a hiding function which, once composed with the original program, leads to the identification of the intended slice. Going through a number of examples, the paper suggests this approach may be an interesting, even if not completely general, alternative to slicing functional programs.

Abstract

Abstract

Abstract
Three-dimensional graphical applications can provide an added value to Location Based Mobile Services (LBMS). This is particularly true for the applications related to urban environments, which can interactively present three-dimensional models to the user, visualized in accordance to his location. Modelling an urban environment is mainly a manual procedure and so it can become a difficult, tedious and time consuming task, due to the many different geometries, textures, details, etc, involved in the urban structures. This paper presents the XL3D modelling system that provides, in an automatic fashion, three-dimensional models of urban areas to be used in a LBMS Project. The XL3D modelling system is based on interoperable access to digital data, in diverse formats, accessing XML documents or invoking Web services in a distributed architecture. The system is driven by L-systems based modelling processes that automatically generate three-dimensional models of urban environments, specified in a declarative mode using documents based on an XML Schema, also called XL3D. Copyright © 2005 by the Association for Computing Machinery, Inc.

Abstract

Abstract